Nitrogen is one of the most important nutrients required for high onion yields. Onions are known as gross feeders and crops can remove 2-3 kg of nitrogen for every ton harvested.
Studies with calcium nitrate confirm this is one of the most effective forms for high yields.
Potassium is important for high yields in onion crops.
It is the second most utilised nutrient and uptake peaks during bulb formation and enlargement. However, care has to be taken as over-application can lead to yield reductions.